A safety fuse is an overcurrent protection facility, which interrupts the current circuit by fusing one or more fuse elements, if the current strength exceeds a specific value over a specific period of time. A safety fuse typically consists of an insulated body comprising two electrical connections, which are connected to one another inside the insulating body by way of the fuse element. The fuse element is heated by the current flowing therethrough, and when the nominal current of the fuse is clearly exceeded for a specific period of time, the fuse element melts to open the circuit.
Safety fuses of this type are used inter alia in the field of electrical installations in so-called electrical power distribution installations. Because space is limited in electrical power distribution installations, the electrical line to be fused is divided into several lines which are electrically connected in parallel with one another. The several lines are also fused in each instance with their own safety fuse. Here the maximum current strength across each of the several lines is reduced accordingly depending on the safety fuse of each of the several lines, so that narrower and flatter fuse bodies can be used in the electrical power distribution installation. By dividing the current across several fused lines, compact electrical power distribution installations can be used. Furthermore, the power loss and the I2t value are reduced by the parallel connection of the safety fuses.
In an electrical power distribution installation having electric lines connected in parallel, problems may arise if individual safety fuses are used therein. For example, problems may arise if the safety fuses can be individually disconnected from an electrical power distribution installation and exchanged for other individual safety fuses. While one may intend to replace a damaged safety fuse, an undamaged safety fuse may accidentally be replaced while the damaged safety fuse remains in the electrical power distribution installation. Furthermore, a safety fuse could be removed from the electrical power distribution installation and accidentally replaced by a safety fuse of a different type (with a correspondingly similar installation size). These possibilities are to be prevented under all circumstances against the background of more stringent procedures to ensure these problems do not occur.